1. Field of the Invention
The present invention relates to a manufacturing method of a microcrystalline semiconductor and a manufacturing method of a display device including a thin film transistor formed of a microcrystalline semiconductor.
2. Description of the Related Art
A thin film transistor (hereinafter also referred to as a “TFT”) has widely been used, already in a liquid crystal display application. A TFT is a kind of field-effect transistor, where a semiconductor which forms a channel is formed of a thin film. As for a semiconductor layer which forms a channel, there are a semiconductor layer formed of amorphous silicon and a semiconductor layer formed of polycrystalline silicon. The former has been used for a large-screen panel of a liquid crystal television or the like, and the latter has been used for a miniaturized and high definition monitor screen of a cellular phone or the like.
Meanwhile, microcrystalline silicon is a material which has been known for a long time along with amorphous silicon, and microcrystalline silicon related to a field-effect transistor was reported in 1980s (for example, see Patent Document 1: U.S. Pat. No. 5,591,987). However, a TFT using microcrystalline silicon has been buried between an amorphous-silicon transistor and a polycrystalline silicon transistor up to today; thus, there has been a delay in practical use thereof. Microcrystalline silicon was reported at an academic society level (for example, see Non-Patent Document 1; Toshiaki Arai et al., SID 07 DIGEST, 2007, pp. 1370-1373).